<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <script>
        var str ='这是字符串';
        console.log(typeof str);

        var num = 20;
        console.log(typeof num);

        var bool = true;
        console.log(typeof bool);

        var a;
        console.log(typeof a);

        var b = null;
        console.log(typeof b);

        var obj = {
            name:'老周',
            sayHi: function () {
                console.log('hi');
                
            }
        }
        console.log(typeof obj);
        obj.sayHi();

        var arr = [1,24,30]
       console.log(typeof arr);

       var date = new Date();
       console.log(typeof date);

       var fun = function () {
       }
       console.log(typeof fun);

       var str1 =str.substr(1);
       console.log(str1);
       
       
       
        
        
        
        
        
        
    </script>
</head>
<body>
    
</body>
</html>